Re: Getting "absolute time" in Linux



Boris Benenson <boris.benenson@xxxxxxxxxxx> writes:

Is there a way in either standard or Real-time Linux to get "absolute
number of ticks (or seconds) since the Epoc (or some other
configurable starting point), regardless of the kernel clock resets
via settimeofday() and the RTC resets via hwclock set and regardless
of the system reboots?

http://www.opengroup.org/onlinepubs/000095399/functions/clock_gettime.html
CLOCK_MONOTONIC

`man clock_gettime' on this Linux box says:

AVAILABILITY
On POSIX systems on which these functions are available,
the symbol _POSIX_TIMERS is defined in <unistd.h> to a
value greater than 0. The symbols _POSIX_MONOTONIC_CLOCK,
_POSIX_CPUTIME, _POSIX_THREAD_CPUTIME indicate that
CLOCK_MONOTONIC, CLOCK_PROCESS_CPUTIME_ID,
CLOCK_THREAD_CPUTIME_ID are available. (See also
sysconf(3).)


Availablility of CLOCK_MONOTONIC is system (and not just libc)
specific (for instance stock Linux 2.4 kernels do not have it,
2.6 do)

--
vale
.